2. Field of the Invention
The present invention relates to carbonate esters, carbonate ester compositions, and to plasticized vinyl chloride polymer compositions containing them.
2. Description of the Prior Art
Various organocarbonates are known to the prior art, and some are taught as being useful as plasticizers in vinyl chloride polymer compositions.
For example, U.S. Pat. No. 4,146,522 to J. S. Heckles shows various dialkyl carbonates and monoalkyl monoalkoxyalkyl carbonates and teaches that they are useful as plasticizers for vinyl chloride polymers.
Certain other prior art references show the use of symmetrical phenyl group-containing carbonates as plasticizers. For example, U.S.S.R. Pat. No. 248,203 shows the use of diphenyl carbonate as a plasticizer for vinyl chloride polymers. Also, Belgian Pat. No. 776,193 shows bis(carboxyphenyl)carbonates and also suggests their use as plasticizers.
In addition to the foregoing, certain other references mention other organocarbonates which are not, however, suggested for use as plasticizers in vinyl chloride polymer compositions. Canadian Patent No. 961,999 describes certain dialkylaryl and dialkoxyaryl carbonates which are described as being useful as stabilizers, but not plasticizers, in vinyl chloride polymer compositions. The Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 4, pp. 766-770 (John Wiley and Sons, New York, 1979) describes mixed alkyl aryl carbonate esters, for example, ethyl phenyl carbonate, without indicating that they can be used as plasticizers.